<template>
  <div class="home-page">

    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">

        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li class="nav-item" v-if="user">
                <nuxt-link
                  class="nav-link" 
                  :class="{
                    active: tab === 'your_feed'
                  }"
                  exact
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'your_feed'
                    }
                  }"
                >Your Feed</nuxt-link>
              </li>
              <li class="nav-item">
                <nuxt-link
                  class="nav-link" 
                  :class="{
                    active: tab === 'global_feed'
                  }"
                  exact
                  :to="{
                    name: 'home'
                  }"
                >Global Feed</nuxt-link>
              </li>
              <li v-if="tag" class="nav-item">
                <nuxt-link
                  class="nav-link" 
                  :class="{
                    active: tab === 'tag'
                  }"
                  exact
                  :to="{
                    tab: 'tag',
                    tag: tag
                  }"
                ># {{ tag }}</nuxt-link>
              </li>
            </ul>
          </div>

          <div 
            class="article-preview"
            v-for="article in articles"
            :key="article.slug"
          >
            <div class="article-meta">
              <nuxt-link :to="{
                name: 'profile',
                params: {
                  username: article.author.username
                }
              }">
                <img :src="article.author.image" />
              </nuxt-link>
              <div class="info">
                <nuxt-link class="author" :to="{
                  name: 'profile',
                  params: {
                    username: article.author.username
                  }
                }">
                  {{article.author.username}}
                </nuxt-link>
                <span class="date">{{article.createdAt | date("MMM DD,YYYY")}}</span>
              </div>
              <button 
                class="btn btn-outline-primary btn-sm pull-xs-right"
                :class="{active : article.favorited}"  
                @click="onFavorite(article)"
                :disabled="article.favoriteDisabled"
              >
                <i class="ion-heart"></i> {{article.favoritesCount}}
              </button>
            </div>
            <nuxt-link 
              :to="{
                name: 'article',
                params: {
                  slug: article.slug
                }
              }" 
              class="preview-link"
            >
              <h1>{{ article.title }}</h1>
              <p>{{ article.description }}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>

          <!-- 分页列表 -->
          <nav>
            <ul class="pagination">
              <li
                class = "page-item"
                :class="{
                  active: item === page
                }"
                v-for="item in totalPage"
                :key="item"
              >
                <nuxt-link 
                  :to="{
                    name: 'home',
                    query: {
                      page: item,
                      tag: $route.query.tag,
                      tab: tab
                    }
                  }" 
                  class="page-link"
                >{{ item }}</nuxt-link>
              </li>

            </ul>
          </nav>

          <!-- /分页列表 -->
        </div>

        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>

            <div class="tag-list">
              <nuxt-link 
                :to="{
                  name: 'home',
                  query: {
                    tag: item,
                    tab: 'tag'
                  }
                }" 
                class="tag-pill tag-default"
                v-for="item in tags"
                :key = "item"
              >{{ item }}
              </nuxt-link>
            </div>
          </div>
        </div>

      </div>
    </div>

  </div>
</template>

<script>
import  { 
  getArticles, 
  getYourFeedArticles,
  addFavorite,
  deleteFavorite
} from "@/api/article"
import  { getTags } from "@/api/tag"
import { mapState } from "vuex"
export default {
  name: "homePage",
  async asyncData({ query }){
    const page = Number.parseInt(query.page || 1);
    const limit = 20;
    const tab = query.tab || "global_feed"
    const tag = query.tag;

    const loadArticles = tab === "global_feed"
      ? getArticles
      : getYourFeedArticles
    const [articleRes, tagRes] = await Promise.all([
      loadArticles({
        limit,
        offset: (page - 1) * limit,
        tag
      }),
      getTags()
    ])
    const {articles, articlesCount} = articleRes.data;
    const { tags } = tagRes.data;

    // 为每个文章点赞按钮 添加状态，防止重复点击
    articles.forEach(article => {
      article.favoriteDisabled = false
    });


    return {
      articles,
      articlesCount,
      tags,
      limit,
      page,
      tab,
      tag
    }
  },
  watchQuery:["page", "tag", "tab"],
  computed:{
    totalPage(){
      return Math.ceil(this.articlesCount/this.limit)
    },
    ...mapState(["user"])
  },
  methods: {
    async onFavorite (article) {
      console.log(article)
      article.favoriteDisabled = true;
      if(article.favorited){
        // 取消点赞
        await deleteFavorite(article.slug);
        article.favorited = false;
        article.favoritesCount -= 1;
        article.favoriteDisabled = false;
      }else{
        // 添加点赞
        await addFavorite(article.slug);
        article.favorited = true;
        article.favoritesCount += 1;
        article.favoriteDisabled = false;
      }
    }
  }
}
</script>

<style>

</style>